Man has been on the earth about one million years. He_   (manage) to live on every part of the planet, even though some climates have made life difficult. It is thought(different) in skin color are the result of climatic__  .(adapt). For example, people with skin colors of yellow, red, and olive, generally come from areas_ they have had to adapt to other climates. Man's size also seems to  (various) according to climate. People living in colder regions are generally larger than_ living in hotter ones. This difference might be explained_the fact that big people have less skin compared to weight than do small people. The less skin a person has relative to his weight, the easier    is for him to keep warm. As part of the natural environment, climate greatly affects human activities. Climate has a significant    0n agriculture. Climatic factors restrict the kinds of crops that can be grown. Man changes his living habits in order to adjust to climate, but climate  (change) as well, though more slowly. By learning more about his climate, man will find a way to adapt to or control it and live a more comfortable life.